Plant Ecosystem Research Articles

Mycorrhizal Symbiosis in Plant Growth and Stress Adaptation: From Genes to Ecosystems.

Plant roots associate with diverse microbes (including bacteria, fungi, archaea, protists, and viruses) collectively called the rhizosphere microbiome. Among them, mycorrhizal fungi colonize host roots and improve their access to nutrients, usually phosphorus and nitrogen. In exchange, plants deliver photosynthetic carbon to the colonizing fungi. This nutrient exchange affects key soil processes, the carbon cycle, and plant health and therefore has a strong influence on the plant and microbe ecosystems. The framework of nutrient exchange and regulation between host plant and arbuscular mycorrhizal fungi has recently been established. The local and systemic regulation of mycorrhizal symbiosis by plant nutrient status and the autoregulation of mycorrhizae are strategies by which plants maintain a stabilizing free-market symbiosis. A better understanding of the synergistic effects between mycorrhizal fungi and mycorrhizosphere microorganisms is an essential precondition for their use as biofertilizers and bioprotectors for sustainable agriculture and forestry management. Expected final online publication date for the Annual Review of Plant Biology, Volume 74 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Understory vegetation diversity, soil properties and microbial community response to different thinning intensities in Cryptomeria japonica var. sinensis plantations.

Soil microorganisms are the key factors in elucidating the effects of thinning on tree growth performance, but the effects of vegetation and soil on the species composition and function of soil microorganisms after thinning are still not well elaborated. The effects of thinning on understory vegetation diversity, soil physicochemical properties and soil microbial community composition were investigated in a thinning trial plantation of Cryptomeria japonica var. sinensis, including four thinning intensities (control: 0%, LIT: 20%, MIT: 30% and HIT: 40%), and the relationships of the microbial community structure with the understory vegetation diversity and soil properties were assessed. The results showed that thinning had a greater effect on the diversity of the shrub layer than the herb layer. The soil bulk density and the contents of soil organic matter, total potassium and nitrogen increased with increasing thinning intensities. The Shannon and Chao indices of soil bacteria and fungi were significantly lower in the LIT, MIT and HIT treatments than in the control. Thinning can significantly increase the abundance of Proteobacteria and Actinobacteria, and higher thinning intensities led to a higher relative abundance of Ascomycota and a lower relative abundance of Basidiomycota, Rozellomycota, and Mortierellomycota. Redundancy analysis indicated that soil physicochemical properties rather than understory vegetation diversity were the main drivers of microbial communities, and fungi were more sensitive to soil properties than bacteria. Functional prediction showed that thinning significantly reduced the potential risk of human diseases and plant pathogens, and the nitrogen fixation capacity of bacteria was the highest in the HIT treatment. Thinning significantly increased the relative abundance of cellulolysis and soil saprotrophs in bacteria and fungi. The findings provide important insights into the effects of thinning on C. japonica var. sinensis plantation ecosystems, which is essential for developing thinning strategies to promote their ecological and economic benefits.

Diversity of home garden plants and their contribution to promoting sustainable livelihoods for local communities living near Serbajadi protected forest in Aceh Timur region, Indonesia

ABSTRACT Home gardens are traditional agroforestry systems that promote plant diversity and ecosystem services while also having direct and positive impacts on human livelihoods. Even though home gardens are considered biodiversity hotspots and have recently been recognised as essential for their role in tropical biodiversity conservation, the benefits of ecosystem services provided by home gardens are understudied. This study investigated plant diversity and ecosystem services in tropical home gardens in the Aceh Timur region of Indonesia. Data was collected from 180 home gardens in 12 villages and recorded 173 plant species associated with 16 ecosystem services. The majority of the cultivated plants were fruit and vegetable plants, which played an important role in supporting food security and household income. Home gardens, with their plant species diversity and ecosystem services, played an important role in biodiversity conservation. Home gardens were important not only for improving household livelihoods, but also for the conservation of plant genetic resources and nearby protected forests.

Differential effect of climate of origin and cultivation climate on structural and biochemical plant traits

Abstract Exploring patterns and causes of intraspecific trait variation is crucial for a better understanding of the effects of climate change on plant populations and ecosystems. However, our current understanding of the intraspecific trait variation is mainly based on structural (morphological) traits, and we have limited knowledge on patterns and causes of variation in biochemical traits (e.g. leaf pigments), which are also crucial for plant adaptation. As a result, we also do not know how similar the climatic effects on structural versus biochemical traits are. Using plant traits from 110 genotypes representing 11 Festuca rubra populations grown in 4 different climates, we studied trait covariation among structural traits (linked to fitness, resource use, gas exchange and reproduction) and biochemical traits (linked to photosynthesis, photoprotection and oxidative stress). We also disentangled the relative role of the climate of origin and the climate of cultivation in the structural versus biochemical traits and tested for adaptive plasticity in the traits. We found that (1) biochemical traits did not covary with structural traits and represent independent ‘photoharvesting–photoprotection’ strategy dimension of functional variation; (2) interactive effects of climate of origin and cultivation were more pronounced for biochemical than structural traits. (3) Trait plasticity was affected by the climate of origin (precipitation and temperature as well as their interaction); (4) F. rubra showed both adaptive and maladaptive plasticity, and adaptiveness depended upon trait type, cultivation climate and climate of origin. Overall, our results suggest that structural and biochemical plant traits respond differentially to climate and thus the response of one group of traits cannot be predicted from the other. Responses are also strongly determined by interactions between the climate of origin and cultivation. Thus, more studies on variation in biochemical traits, their correspondence to other traits, and their variation with climate are needed. Read the free Plain Language Summary for this article on the Journal blog.

Nitrogen Preference of Dominant Species during Hailuogou Glacier Retreat Succession on the Eastern Tibetan Plateau

Plant nitrogen (N) uptake preference is a key factor affecting plant nutrient acquisition, vegetation composition and ecosystem function. However, few studies have investigated the contribution of different N sources to plant N strategies, especially during the process of primary succession of a glacial retreat area. By measuring the natural abundance of N isotopes (δ15N) of dominant plants and soil, we estimated the relative contribution of different N forms (ammonium-NH4+, nitrate-NO3- and soluble organic N-DON) and absorption preferences of nine dominant plants of three stages (12, 40 and 120 years old) of the Hailuogou glacier retreat area. Along with the chronosequence of primary succession, dominant plants preferred to absorb NO3- in the early (73.5%) and middle (46.5%) stages. At the late stage, soil NH4+ contributed more than 60.0%, In addition, the contribution of DON to the total N uptake of plants was nearly 19.4%. Thus, the dominant plants' preference for NO3- in the first two stages changes to NH4+ in the late stages during primary succession. The contribution of DON to the N source of dominant plants should not be ignored. It suggests that the shift of N uptake preference of dominant plants may reflect the adjustment of their N acquisition strategy, in response to the changes in their physiological traits and soil nutrient conditions. Better knowledge of plant preferences for different N forms could significantly improve our understanding on the potential feedbacks of plant N acquisition strategies to environmental changes, and provide valuable suggestions for the sustainable management of plantations during different successional stages.

Effects of thinning on soil nutrient availability and fungal community composition in a plantation medium-aged pure forest of Picea koraiensis

Thinning is an important silvicultural practice for improving the productivity and wood production in plantation forest. Different intensities of thinning management can affect tree growth and alter soil nutrient effectiveness, thus affecting soil fungal community structure and diversity. Our objective is to determine the soil factors and their regulatory mechanisms that influence stand growth by thinning, and to provide data to support the establishment of large diameter timber cultivation technology for Picea koraiensis. In this study, we conducted medium- and high-intensity thinning in 43a P. koraiensis plantation middle-aged forests and investigated the growth indexes, soil physicochemical properties, and fungal community diversity in rhizosphere and non-rhizosphere soils of the stands after thinning at different densities (904 plants/ha for control, 644 plants/ha for 30% thinning intensity, and 477 plants/ha for 50% thinning intensity). The results showed that all growth indicators (annual growth of tree height, diameter at breast height, height under live branches and crown width) of the plantation after high-intensity thinning (477 plants/ha) were higher than those of the control (no thinning, significant) and medium-intensity thinning (644 plants/ha). Mycorrhizal infection rate was higher at the beginning of the growing season than at the end of the growing season, and increased slightly with decreasing stand density. Compared to the control, all medium- and high-intensity thinning treatments significantly improved soil nutrient content (P < 0.05), including total carbon, total nitrogen, total phosphorus, total potassium, Available phosphorus and Available potassium. Fungal diversity was higher but lower in abundance than the control in both rhizosphere and non-rhizosphere soils after thinning. The number of OTUs and fungal richness and diversity indices of non-rhizosphere soil fungi were higher than those of rhizosphere soil fungi. In conclusion, this study provides new evidence that reasonable intercalation can increase the radial and vertical growth of P. koraiensis plantation forests and promote the diversity of subsurface soil fungal communities. It is shown that thinning intensity regulates biogeochemical cycles in P. koraiensis plantation ecosystems by affecting soil nutrients and fungal community structure. Therefore, 50% thinning intensity can be used to increase timber production in plantation forests during large diameter timber cultivation of P. koraiensis and improve predictions associated with achieving long-term forest management strategies.

Modeling Collaborative Behaviors in Energy Ecosystems

The notions of a collaborative virtual power plant ecosystem (CVPP-E) and a cognitive household digital twin (CHDT) have been proposed as contributions to the efficient organization and management of households within renewable energy communities (RECs). CHDTs can be modeled as software agents that are designed to possess some cognitive capabilities, enabling them to make autonomous decisions on behalf of their human owners based on the value system of their physical twin. Due to their cognitive and decision-making capabilities, these agents can exhibit some behavioral attributes, such as engaging in diverse collaborative actions aimed at achieving some common goals. These behavioral attributes can be directed to the promotion of sustainable energy consumption in the ecosystem. Along this line, this work demonstrates various collaborative practices that include: (1) collaborative roles played by the CVPP manager such as (a) opportunity seeking and goal formulation, (b) goal proposition/invitation to form a coalition or virtual organization, and (c) formation and dissolution of coalitions; and (2) collaborative roles played by CHDTs which include (a) acceptance or decline of an invitation based on (i) delegation/non-delegation and (ii) value system compatibility/non-compatibility, and (b) the sharing of common resources. This study adopts a simulation technique that involves the integration of multiple simulation methods such as system dynamics, agent-based, and discrete event simulation techniques in a single simulation environment. The outcome of this study confirms the potential of adding cognitive capabilities to CHDTs and further shows that these agents could exhibit certain collaborative attributes, enabling them to become suitable as rational decision-making agents in households.

Plant attributes interact with fungal pathogens and nitrogen addition to drive soil enzymatic activities and their temporal variation

Abstract Nitrogen enrichment can alter soil communities and their functioning directly, via changes in nutrient availability and stoichiometry, or indirectly, by changing plant communities or the abundance of consumers. However, most studies have only focused on one of these potential drivers and we know little about the relative importance of the different mechanisms (changes in nutrient availability, in plant diversity or functional composition or in consumer abundance) by which nitrogen enrichment affects soil functioning. In addition, soil functions could vary dramatically between seasons; however, they are typically measured only once during the peak growing season. We therefore know little about the drivers of intra‐annual stability in soil functioning. In this study, we measured activities of β‐glucosidase and acid phosphatase, two extracellular enzymes that indicate soil functioning. We did so in a large grassland experiment which tested the effects, and relative importance, of nitrogen enrichment, plant functional composition and diversity, and foliar pathogen presence (controlled by fungicide) on soil functioning. We measured the activity of the two enzymes across seasons and years to assess the stability and temporal dynamics of soil functioning. Overall β‐glucosidase activity was slightly increased by nitrogen enrichment over time but did not respond to the other experimental treatments. Conversely, plant functional diversity and interactions between plant attributes and fungicide application were important drivers of mean acid phosphatase activity. The temporal stability of both soil enzymes was differently affected by two facets of plant diversity: species richness increased temporal stability and functional diversity decreased it; however, these effects were dampened when nitrogen and fungicide were added. The fungicide effects on soil enzyme activities suggest that foliar pathogens can also affect below‐ground processes and the interacting effect of fungicide and plant diversity suggests that these plant enemies can modulate the relationship between plant diversity and ecosystem functioning. The contrasting effects of our treatments on the mean versus stability of soil enzyme activities clearly show the need to consider temporal dynamics in below‐ground processes, to better understand the responses of soil microbes to environmental changes such as nutrient enrichment. Read the free Plain Language Summary for this article on the Journal blog.

Precipitation preferences alter the relative importance of herbaceous plant diversity for multifunctionality in the drylands of China

BackgroundMultiple components of biodiversity are excellent predictors of precipitation-induced changes in ecosystem function. However, the importance of differing scales (alpha versus beta) is usually overlooked in biodiversity–ecosystem multifunctionality studies. Consequently, little is known about how precipitation regulates the relationship between multifunctionality and multiple components of alpha and beta diversity.AimsWe investigated geographic patterns of herbaceous plant diversity and ecosystem multifunctionality along a precipitation gradient spanning more than 2010 km in Northwest China.MethodsWe assessed the effects of herbaceous species, phylogenetic, and functional components at different scales on multifunctionality in drylands.ResultsThe alpha diversity of species and functional beta diversity were key components explaining the variation in multifunctionality. As the main environmental factor, MAP (mean annual precipitation) affected multifunctionality by changing the mediating variables (i.e., species alpha and functional beta diversity). More importantly, a certain precipitation threshold was detected for the relationship of multifunctionality to species alpha and functional beta diversity. MAPs of approximately 158 mm and 140 mm modulated this relationship (shifting it from uncorrelated to significantly correlated).ConclusionsOur findings provide insights into previously neglected mechanisms by which diversity in herbaceous layers at different scales affects ecosystem multifunctionality. It is highlighted that MAP regulates the relationship between diversity and multifunctionality in dryland ecosystems at different scales. Further, diversity may have substantial consequences for multifunctionality where MAP is higher. These empirical results provide a comprehensive understanding of the biodiversity–multifunctionality relationship in the context of precipitation, ultimately contributing to conservation and restoration programs for multifunctionality in drylands.

Linking Rhizosphere Soil Aggregates with Belowground and Aboveground Plant Traits

Rhizosphere soil ecosystems are represented by the diversity of different soil aggregate-size classes, such as large macroaggregates, small macroaggregates, mesoaggregates, and microaggregates. Though these aggregate-size classes represent distinct biological, chemical, and physical properties, little is known about their dynamics and relationships with belowground and aboveground plant traits. In this study, we examined the relationships of various soil aggregate-size classes and their organic carbon contents with many aboveground and belowground soybean plant traits. Our study revealed several novel and interesting relationships between soil structural properties and plant traits. Notably, small macroaggregates represented a major portion of the rhizosphere soil ecosystem of soybean plants while organic carbon contents decreased with decreasing size of soil aggregates. Only microaggregates showed a significant relationship with root architectural traits, such as length and surface area. Among all soil aggregate size classes, the abundance of small macroaggregates and the organic carbon contents of microaggregates were better correlated with plant traits. In general, organic carbon contents of different soil aggregate-size classes showed positive correlations with leaf trichome density (defense traits) and major macronutrients, such as root P, K, and S contents; while there were mostly negative correlations with some micronutrient (Ca, Mn, Zn, Cu, B, and Mg) contents of roots and shoots. However, the abundance of small macroaggregates mostly positively correlated with the mineral contents of plant roots and shoots. Collectively, the positive and negative correlations of organic carbon contents of different soil aggregate-size classes with trichomes (defense) and physiological traits (micro-mineral contents) suggest their significance in plant nutrition and defense. Though our results suggest the relationships of soil aggregate properties with aboveground and belowground traits, further research is needed to discern the role of soil structural traits in mediating plant growth, development, defense, and physiology.

Unravelling the relationship between plant diversity and vegetation structural complexity: A review and theoretical framework

AbstractVegetation structural complexity (VSC)—the three‐dimensional distribution of plants within an ecosystem—is an important ecological trait. To date, research has focused primarily on theeffectsof VSC on ecological patterns and processes, but comparatively little is known about what drives variation in VSC.Recent advances in active remote sensing technology, particularly light detection and ranging and radio detection and ranging, have allowed the measurement of VSC at unprecedented spatial scales and resolutions. Out of this and earlier work has emerged evidence that VSC is typically associated with greater ecosystem functioning (especially microclimate regulation, productivity, faunal diversity and habitat provisioning), making restoration of vegetation complexity a potentially powerful restoration tool.Recent studies of VSC across natural and experimental gradients of plant diversity have also revealed that more diverse plant communities tend to be more structurally complex. However, the shape and generality of this relationship—and the mechanism(s) by which phytodiversity might contribute to structural complexity—remain poorly understood.Here, we review how active remote sensing has facilitated recent VSC research and shaped our understanding of the relationship between vegetation complexity and ecosystem function. We then present a theoretical framework for the relationship between phytodiversity and VSC based on classic biodiversity‐ecosystem functioning principles. Finally, we evaluate the evidence for the notion that diverse plant assemblages tend to be more structurally complex and explore the shape of the relationship between phytodiversity and VSC using data from 13 recent remote sensing studies.Synthesis. The relationship between phytodiversity and VSC appears to be almost universally positive. Preliminary evidence further suggests that the most common relationships between phytodiversity and VSC are linear or saturating, indicating that the extent of functional redundancy between species varies across plant communities and ecosystems. In contrast, we find little evidence for exponential or negative relationships between plant diversity and VSC, suggesting that even modest increases in plant diversity could markedly increase structural complexity. Additional investigations of phytodiversity‐VSC relationships are necessary to establish whether the observed positive relationships are causal (and, if so, in which direction) and to clarify the potential impact of plant community restoration on structural complexity and broader ecosystem function.

REMOTE SENSING IN BIOMETEOROLOGY

Remote sensing is a powerful tool used in biometeorology to study the interactions between the atmosphere and living organisms, particularly plants. Through satellite-based sensors, researchers can observe and analyze a range of biophysical parameters related to vegetation, such as leaf area index, biomass, vegetation cover, and land surface temperature. This data can be used to estimate plant growth, productivity, and water use efficiency, as well as monitor environmental conditions, such as drought, heat stress, and air pollution. Remote sensing is used in the development of crop models for agricultural management and to study the impact of climate change on plant communities and ecosystems. By tracking changes in vegetation cover and productivity, as well as changes in phenology, remote sensing helps researchers identify optimal planting times, irrigation schedules, and predict crop yields.

Population dynamics of Spirostachys africana Sond. a species highly exploited amongst some communities of Limpopo Province, South Africa

Abstract. Victor PM, Tshisikhawe MP, Magwede K. 2023. Population dynamics of Spirostachys africana Sond. a species highly exploited amongst some communities of Limpopo Province, South Africa. Biodiversitas 24: 492-497. Over-exploitation of important indigenous plant species impact negatively on their population structure. Unmonitored and unsustainable harvesting from plant ecosystems may inhibit plant recovery. The aim of the study was to investigate the population structure of Spirostachys africana in a communal area of Ha-Matsa Village in Limpopo Province, South Africa. Eleven transects of 100m x 10m were used to sample ecological parameter data from 66 plant specimens of S. africana species. Transects were subjectively placed within the population of S. africana. Data on plant height size classes and basal stem diameter size classes exhibited an almost Bell-shaped population curve. The population of S. africana did not have many seedlings, with the Crown health status data revealing a population with generally moderately damaged crowns (24%), while 19% of individuals had healthy crowns. The concern is the recorded 9% of dead crowns. Although the population looks great from a distance, the sampled ecological data revealed an unviable population. The Spirostachys africana population of Ha-Matsa Village does not have more individuals in the small size classes of both height and basal stem diameter. Conservation practice implies that if anthropogenic activities are not properly monitored, there may not be enough young individuals to support the population of S. africana into the future. Therefore, this study aimed to improve the assessment and the effects of harvesting on the S. africana species population. This study also suggests important information and guides ecologists and conservationists on sustainable harvesting practices and offtakes of S. africana.

STABILITY ANALYSIS OF DYNAMICAL MODEL INTERACTIONS TEA PLANTS, PESTS, AND DISEASES WITH FUNGICIDES AND INSECTICIDES CONTROLS

Tea plants are one of the exports commodities in Indonesia. In their development, the plantation ecosystem is heavily influenced by several factors, both internal and external factors. In the field of applied mathematics, mathematical modelling can be used to analyze the development of tea plant growth and their interactions each other in their ecosystem. The mathematical model in this research is combining three main models, there are logistic model, epidemiological model, and predator prey model by adding fungicide and insecticide controls. Furthermore, local and global stability analysis is carried out and the optimal control problem is solved by Pontryagin maximum principle. The results of the analysis obtained five equilibrium points. Local stability analysis was carried out using the Routh Hurwitz criteria which showed the fifth equilibrium point is locally asymptotically stable. The basic reproduction number in the model is 0.99. Because 16R0&lt;1" style="width: 28pt; height: 11pt;"&gt;, it can be concluded that there is no spread of disease in the tea plantation ecosystem after a period of 5 years. The control provided can reduce pest and disease attacks. After being given control, the population of infected tea plants decreased by 93.21%, Empoasca pests decreased by 99.47%, and leaf roller caterpillars decreased by 99.31% compared to the model that was not given control.

Seven years phosphorus addition has no effect on soil acidity in two tropical plantations

Strong acidity accompanied by low phosphorus (P) availability occurs in tropical soils especially under high nitrogen (N) deposition. Commonly, improved P availability can mitigate soil acidity in tropical natural forests via direct reaction with acidic cations or impacting plant uptake and soil microbial community to indirectly regulate soil cations. However, whether P input can alleviate soil acidity in tropical plantations remains unknown. This study selected two tropical typical plantations (dominated by Acacia auriculiformis and Eucalyptus urophylla, respectively), to investigate the effects of seven years of P addition on soil acidity and the underlying mechanisms. The results showed that P addition did not change soil pH or cation concentrations, suggesting no variations in soil acidity under P addition. Moreover, P addition did not affect acidic cation concentrations within plant tissues, soil microbial community, litterfall input, and fine-root biomass, indicating that P addition did not impact the processes of plant and soil microbes to regulate the dynamics of soil cations to alleviate acidity. However, we found significant increases in soil available P, soil total P, and plant P concentrations, indicating that added P led to P enrichment in soil and plants. In addition, a consistent response of soil acidity in two tropical plantation ecosystems was observed under combined N with P addition. Our findings improve the understanding of the relationships between P availability and soil acidification in tropical forests and highlight the necessity to accurately evaluate the role of P in acidic tropical forest soils.

Long-Term Vegetation Changes and Socioeconomic Effects of River Engineering in Industrialized Areas (Southern Poland).

The exploitation of mineral resources associated with human mining activities leads to the degradation of both terrestrial and aquatic biocenotic systems. The drastic disturbance of water relations as a result of the relocation of the riverbed of the Biala Przemsza River (southern Poland) for coal and filler sand mining will lead to changes in plant ecosystems. The purpose of this study was to determine and compare the diversity and distribution of vegetation in the Biała Przemsza valley in sections of channel straightening with the old riverbed and areas undisturbed by engineering works against the background of land use in temporal and spatial aspects. The results of the ecological and phytosociological studies showed that the composition of flora and vegetation types varied. Within the transformed riverbed, anthropogenic mixed forests with species characteristic of different ecological systems are developing, whereas the non-regulated section of the river is overgrown by an alder riparian forest with an almost complete species composition for this plant community. The highest Simpson's biodiversity index was found in the anthropogenically disturbed section of the river (0.86), and in the undisturbed section, it was 0.83. Both sections of the river were dominated by species of the family Compositae, Poaceae, Caryophyllaceae, Rosaceae and Apiaceae. The diversity of the flora in the transformed sections of the valley is determined by the presence of mosaics and microhabitats, as well as the nature of the surrounding vegetation, which is reflected in the ecological requirements of the flora concerning light preference (moderate light [56.25%]), and almost 90% of the flora from the area of the regulated section of the valley develops on humus-poor and mineral-humus soils. Although this area has lost its original natural function, it is now valuable for selected economic and social functions, especially in highly urbanized regions.

Grazing intensity alters the plant diversity–ecosystem carbon storage relationship in rangelands across topographic and climatic gradients

AbstractPlant diversity supports multiple ecosystem functions, including carbon sequestration. Recent shifts in plant diversity in rangelands due to increased grazing pressure and climate changes have the potential to impact the sequestration of carbon in arid to semi‐humid regions worldwide. However, plant diversity, grazing intensity and carbon storage are also influenced by environmental factors such as nutrient availability, climate and topography. The complexity of these interactions limits our ability to fully assess the impacts of grazing on biodiversity–ecosystem function (BEF) relationships.We assessed how grazing intensity modifies BEF relationships by determining the links between plant diversity and ecosystem carbon stocks (plant and soil carbon) across broad environmental gradients and different plant growth forms. To achieve this, we surveyed 1493 quadrats across 10 rangelands, covering an area of 23,756 ha in northern Iran.We show that above‐ground carbon stocks increased with plant diversity across topographic, climatic and soil fertility gradients. The relationship between above‐ground carbon stocks and plant diversity was strongest for forbs, followed by shrubs and grasses. Soil carbon stocks increased strongly with soil fertility across sites, but aridity, grazing, plant diversity and topography were also important in explaining variation in soil carbon stocks. Importantly, above‐ground and soil carbon stocks declined at high grazing intensity, and grazing modified the relationship between plant diversity and carbon stocks regardless of differences in abiotic conditions across sites.Our study demonstrates that relationships between plant diversity and ecosystem carbon stocks persist across gradients of aridity, topography and soil fertility, but the relationships are modified by grazing intensity. Our findings suggest that potential losses in plant diversity under grazing intensification could reduce ecosystem carbon storage across wide areas of arid to semi‐humid rangelands. We discuss the potential mechanisms underpinning rangeland BEF relationships to stimulate future research.Read the freePlain Language Summaryfor this article on the Journal blog.

Effects of Long-Term Application of Earthworm Bio-Organic Fertilization Technology on Soil Quality and Organo-Mineral Complex in Tea Garden

Soil quality is crucial for plant productivity and environmental quality sustainability. Applying bio-organic fertilizer to achieve sustainable agriculture has become popular. Tea garden soil which had been fertilized for 12 years was chosen for the study, and soil quality and microaggregate composition were studied. The results showed that earthworm bio-organic fertilizer treatment could increase the indicators of soil’s physical and chemical properties such as total carbon and total nitrogen in soil. Bio-organic fertilization technology could significantly increase the number and activity of soil microorganisms, and upgrade soil enzyme activity which was related to soil nutrients. Specifically, the activities of urease in soil were markedly enhanced due to the implication of bio-organic fertilizer. Additionally, SR-FTIR analysis revealed that clay minerals were connected as nuclei with the capacity to bind carbon, and that this interaction was aided by organic fertilization. Specifically, the replacement of chemical fertilizer with organic fertilizer can improve the ability of clay minerals and iron/aluminum/silicon oxides to protect aliphatic groups, polysaccharides and proteins. In conclusion, continuous organic amendments initialize a positive feedback loop for the maintenance of the organic–mineral complex in soils, which can contribute to enhanced soil organic carbon (SOC) storage. These results confirmed the feasibility of organic fertilizer for soil quality improvement in tea plantation ecosystems.

A ‘Get‐Save‐Return’ process continuum runs on phosphorus economy among subtropical tree species

Abstract Plants allocate nutrients to new leaves via making a cost–benefit trade‐off between root nutrient absorption (‘get’) and leaf nutrient resorption (‘save’). This active trade‐off in nutrient acquisition pathways may cause a passive trade‐off between resorption and decomposition (‘return’). However, whether these nutrient‐associated processes are linked and form a ‘get‐save‐return’ (GSR) continuum, and its linkages with the above‐ground leaf economics spectrum (LES) and the below‐ground mycorrhizal association remain unclear. Here, we present the first empirical evidence of a direct link among multiple nutrient‐associated processes and tested this continuum hypothesis by synchronously integrating root nutrient absorption, leaf nutrient resorption and leaf litter decomposition of 15 co‐occurring tree species hosting either arbuscular mycorrhizal or ectomycorrhizal fungi in subtropical forests of China. Across species, there was an active trade‐off between phosphorus (P) absorption and resorption, which further caused a passive trade‐off between P resorption and leaf litter decomposition, indicating that the GSR continuum exists and runs on P economy. However, these processes associated with nitrogen economy were not well linked. Interestingly, the loading scores of species on the LES were positively correlated with root P absorption, negatively with leaf P resorption and positively with leaf litter decomposition. These linkages indicate that species running in the ‘fast lane’ had greater root P absorption, lower leaf P resorption and faster leaf litter decomposition than species running in the ‘slow lane’, and that the process‐based GSR continuum follows the trait‐based ‘fast‐slow’ LES. Furthermore, the continuum on P economy emerged evidently in the ectomycorrhizal tree species rather than in the arbuscular mycorrhizal tree species, indicating critical control of mycorrhizal association over the continuum. Synthesis. Overall, these results demonstrate the existence of the GSR continuum on tree P economy, which conforms to the economics spectrum theory but varies with mycorrhizal association type. Our findings provide a process‐based framework for mechanistic understanding of the whole plant nutrient economy and ecosystem nutrient cycling, and facilitate improved predictions of biogeochemical models.

Response of plant element traits to soil arsenic stress and its implications for vegetation restoration in a post-mining area

The ecological environment in mining area is fragile, and the carbon (C), nitrogen (N), and phosphorus (P) content of dominant plants is closely related to plant nutrient limitation, community composition and ecosystem function. Clarifying the response of dominant plants to soil properties and the corresponding trade-off mechanism are essential for rebuilding the ecological resilience and self-sustaining ability of mining areas. In order to explore the response of dominant plant element traits to soil physico-chemical properties under the stress of soil arsenic (As) pollution, an abandoned metal mining area threatened by heavy soil As pollution was selected as the research area, the soil physico-chemical properties and soil As content in different speciation, and the contents of C, N and P in dominant plants were measured. The results showed that: (1) The soil As pollution was serious in the mining area, while the contents of soil nutrient were relatively low. (2) The soil As content in different speciation affected the absorption and utilization of P by plants. (3) The dominant plants responded to soil As toxicity by allocating more nutrients to leaves to reduce toxicity and ensure growth. This study helps to reveal the nutrient driving law of plant diversity processes and community succession in heavy metal-contaminated sites and is of great significance to restore the fragile ecosystems in mining areas.